Preheat oven to 350 degrees F.
Place the lamb, onion, garlic, beaten egg, fresh herbs, lemon zest, pine nuts, cinnamon, cardamom, and salt and pepper into a large bowl. Mix everything together using your fingertips. You want to get all the ingredients evenly distributed without compacting the meat.
Form about 10 meatballs from the mixture. You can do this several hours ahead of time if you want, but be sure to cover the meat completely with plastic wrap and refrigerate until needed.
Cover the bottom of a heavy pan with 1 1/2 tablespoons olive oil and heat until hot.
Work in batches so you don't crowd the pan, and brown the meatballs on all sides for about 4 minutes. Add more oil as necessary.
Place the meatballs on a baking sheet and bake for about 12-15 minutes, or until cooked through. Or you can continue to cook them on the stovetop, but it takes longer to get them cooked all the way the way through.
Meanwhile make the sauce by mixing the tahini garlic, lemon juice and salt, then adding enough water to make a thin sauce. Salt it to taste.
Serve the meatballs hot from the oven, nestled in the sauce. Garnish with more pine nuts, herbs, atop rice, quinoa, or even orzo pasta.